Canon EOS 5D Mark III Instruction Manual (en)

Live View Shooting Cautions
Image Quality
When you shoot at high ISO speeds, noise (dots of light, banding, etc.) 
may become noticeable.
Shooting in high temperatures may cause noise and irregular colors in 
the image.
If Live View shooting is used continuously for a long period, the camera’s 
internal temperature may rise, degrading image quality. Stop Live View 
shooting when not shooting images.
If you shoot a long exposure while the camera’s internal temperature is 
high, image quality may be degraded. Stop Live View shooting and wait 
a few minutes before shooting again.
White <s> and Red <E> Internal Temperature Warning
If the camera’s internal temperature increases due to prolonged Live 
View shooting or a high ambient temperature, a white icon <s> will 
appear. If you continue shooting while this icon is displayed, the image 
quality may degrade. You should stop the Live View shooting and allow 
the camera to cool down before shooting again.
If the camera’s internal temperature further increases while the white icon 
<s> is displayed, a red icon <E> will start blinking. This blinking icon is a 
warning that the Live View shooting will soon end automatically. If this 
happens, you will not be able to shoot again until the camera’s internal 
temperature decreases. Turn off the power and let the camera rest for a while.
Using Live View shooting at a high temperature for a prolonged period 
will cause the <s> and <E> icons to appear earlier. When you are not 
shooting, turn off the camera.
If the camera’s internal temperature is high, the image quality of high ISO 
speed images or long exposures may be degraded even before the 
white icon <s> is displayed.
Shooting Result
If you take the picture in magnified view, the exposure may not come out 
as desired. Return to the normal view before taking the picture. In 
magnified view, the shutter speed and aperture will be displayed in 
orange. Even if you take the picture in magnified view, the image will be 
captured in the normal view.
If [z2: Auto Lighting Optimizer] (p.144) is not set to [Disable], the 
image may look bright even if a decreased exposure compensation or 
decreased flash exposure compensation has been set.